Vets decided the fish needed an operation and it would have to be done out of water.

"We had to move quickly to help Mini," said Jonny Rudd, assistant curator of the aquarium.

"The eye was very swollen so it became apparent she was going to need an operation. The intricacy of the area meant it was also apparent it would need to be done out of the water."

Maintaining anaesthesia in a fish out of water can be challenging, as it involves constantly passing medicated water over the gills of the fish and keeping the skin wet.

A team of vets managed to remove the eye in an operation that lasted one hour.

Once the anaesthetic had worn off Mini was returned to a tank behind the scenes where she was given antibiotics and lots of treats, including mussels in shells or her favourite, shore crabs. She is now back where she belongs, swimming happily in her tank.

"The lack of eye doesn't seem to bother her," said Mr Rudd. "The guests still love her and often ask about how she's doing. She's an important part of our aquarium family so it's great to see her settled and doing so well."